Finding Gold, of a Sort, in Landfills

By BARRY MEIER,

Published: September 7, 1993

LANCASTER, Pa., Sept. 1—
While most cities are still struggling to recycle today's trash, officials here have taken a novel approach to the waste problem -- they are mining yesterday's garbage.

At a municipal landfill nestled in rolling farmland along the Susquehanna River about 10 miles west of here, the detritus that is dug up helps feed a nearby incinerator that supplies electricity for more than 15,000 homes.

And landfill space once crammed with garbage is now available for trash that cannot be recycled or burned.

"Some people mine coal for energy, but when we mine, we mine garbage," said Herbert W. Flosdorf, executive director of the Lancaster County Solid Waste Authority, which operates the landfill. Expense of Closing Dumps

The number of communities and businesses that are turning the trash-disposal process on its head is small but growing. They not only recover usable resources and extend the life of dumps, but may also reclaim some that pose environmental threats.

Interest in such activities is heightened by Federal regulations taking effect in October that will require communities, which have been able to essentially ignore dumps they had filled and closed, to monitor shut landfills for 30 years.

Mining can delay the expenditure of millions of dollars in closing costs. Officials in some states like California, where there are already tough landfill closing laws, have begun to investigate the practice.

"This is all about economics," said Randall Forbes, manager of refuse disposal for the Department of Public Works in Mendocino County, Calif., which has begun studying whether to mine its landfill. "The real benefit may be that we can recover landfill space and use it again."

Proponents of garbage mining, however, caution that in many places the cost of digging up garbage can easily exceed that of simply buying new land. And some environmentalists note that it is far easier to recycle materials before they are buried.

"This is not a waste management strategy of the highest order," said Allen Hershkowitz, a senior scientist with the Natural Resources Defense Council, which has its headquarters in New York City. "It underscores the absurdity of entombing everything we throw out."

Federal environmental officials said that it was far too soon to draw any conclusions about mining's benefits or speculate about the impact of new regulations. "This is really cutting-edge stuff that we have not had a chance to evaluate," said Bruce Weddle, director of the municipal waste division of the Environmental Protection Agency.

But it appears that in some cases, mining garbage may save a community money. For example, Collier County, Fla., which includes the city of Naples, has been excavating a landfill to recover an unlikely commodity: the dirt that is spread each day over newly dumped garbage to hold down odors and discourage rodents. This dirt, or cover soil, is extremely expensive in Florida, and officials estimate that they save about $500,000 a year by using the dirt extracted from old garbage mounds to cover newer, smellier, garbage.

As the dirt is excavated, metals, tires and other recyclable materials are also recovered and the rest of the exhumed trash is reburied in a newer part of the landfill that has better environmental protections, said William Lorenz, the country's environmental services administrator.

Some businesses are also looking to landfill mining. Mr. Forbes, the Mendocino County official, told of a lumber company that was hoping to sell dirt and decomposed bark from its landfill to the county for cover soil, and in the process clean up the site and turn it into a marketable piece of property.

Elsewhere, state officials like those in New York are investigating mining as a way of reclaiming problem landfills. In a bid to rejuvenate six dumps that have been ordered closed by state officials, the New York State Energy Research and Power Authority is financing mining projects at the landfills.

The move follows a 1990 experiment at a landfill outside Edinburg, N.Y., near Saratoga Springs, that indicated that some older dumps could be mined safely without releasing toxic materials like asbestos, said Eugene Salerni, an environmental engineer in Albany who directed the project.

But other experts cautioned that such mining could release buried hazards. "This is not much different than what is being done at Superfund sites," said William Rathje, a professor of anthropology at the University of Arizona in Tucson who has studied the history and environmental aspects of landfills. "It does not strike me as something that most local communities would want to mess around with."

The project here in Lancaster County appears to reflect both the potential and limitations of mining garbage. The project's roots stretch back to 1986, when the county decided to close five smaller landfills that no longer meet state standards and opened a 100-acre dump outside the village of Creswell.

Until January 1991, the landfill took in garbage from the county's 425,000 residents and businesses and buried it, producing mounds that were soon 60 feet high. But that month, a garbage incinerator was completed, and there was not enough new trash to run the incinerator at capacity. So officials started excavating 18 acres of the landfill to recover waste that could be burned at the incinerator, said Mr. Flosdorf.

Bulldozers and backhoes dig up old trash at the landfill and dump it into a cylinder-shaped sifter that separates dirt from household waste. Nearly 60 percent of the trash excavated, a hodgepodge of crushed milk cartons, shredded plastic garbage bags and soggy newspapers still showing the headlines of many yesterdays, can be burned in the incinerator.

About 10 percent -- trash like like rubber-backed rugs and bedsprings -- cannot be burned and must be reburied. And the remainder is the dirt, which is used to bury incinerator ash and other waste.

Mr. Flosdorf said the county makes a weekly profit of $4,000 from the electricity produced by the excavated waste, money that offsets the cost of mining. But more important, he estimated that the excavation had decreased the volume of garbage at the 18-acre site by 78 percent, a gain that would extend the dump's life by about four years.

"We don't want to build any more landfills in this county, so we want this one to last as long as possible," he said.

Still, Mr. Flosdorf's enthusiasm about mining is offset by the skepticism of other experts. "Even if this is a viable option, it could be commercially costly," said Mr. Hershkowitz of the Natural Resources Defense Council. "You still have a lot of residue to discard and a lot of buried material that has been contaminated and degraded."

Mr. Rathje, the University of Arizona professor, said he was also cautious about the technique, adding that he believed society's emphasis should remain on recycling new garbage and reducing waste.

But he said that for communities that have decided to use incinerators, mining might make sense. And it could have an even broader appeal if the market for recyclable materials improves enough to make garbage mining cost-effective even without incineration.

"I do believe that somewhere down the line -- perhaps 5 years or perhaps 50 -- mining landfills for resources like aluminum, steel, plastic or the energy in paper is definitely going to be economically viable," he said.

Photo: At a municipal landfill in Creswell, Pa., officials are mining garbage. A cylinder-shaped sifter, center, separated dirt from trash. The detritus that is dug up is fed to a nearby incinerator, which helps power a generator that supplies electricity for more than 15,000 homes. A weekly profit of $4,000 is made. (Bill Cramer for The New York Times) Graph: "Mining Garbage" shows content and financial information pertaining to landfill excavation in Creswell, Pa. (Source: Lancaster County Solid Waste Management Authority)

Correction: September 9, 1993, Thursday An article on Tuesday about mining landfills to recycle old garbage referred incorrectly to a New York State agency that is financing mining projects at dumps. It is the Energy Research and Development Authority.